AEG making high-pitched "Squeal" sound when fired? (updated)

[ThunderCactus]

Sounds to me like your bevel gear is shimmed too far away from the pinion gear
If your still chipping the pinion at maximum height, it's definitely not shimmed right.
It should start out real loud and high pitched at it's lowest engagement point, and when it gets to maximum engagement you'll hear it grind. It's a REALLY obvious change in pitch. Just a little bit under that point, the gears/motor will sound significantly quieter, that's your optimum height.